Solve the Initial-Value Problem $$y ^ { \prime \prime } + 81 y = 0 , y \left( \frac { \pi } { 9 } \right) = 0 , y ^ { \prime } \left( \frac { \pi } { 9 } \right) = 8$$

Multiple Choice

Solve the initial-value problem. $$y ^ { \prime \prime } + 81 y = 0 , y \left( \frac { \pi } { 9 } \right) = 0 , y ^ { \prime } \left( \frac { \pi } { 9 } \right) = 8$$

A) $y ( x ) = - x \sin ( 9 x )$
B) $y ( x ) = \frac { 8 } { 9 } x \sin ( 9 x )$
C) $y ( x ) = - \frac { 8 } { 9 } x \sin ( 9 x )$
D) $y ( x ) = - \frac { 8 } { 9 } \sin ( 9 x )$
E) $y ( x ) = \frac { 8 } { 9 } \sin ( 9 x )$